package _11define._01test;

public class Demo {
    public static void main(String[] args) {
        Father son = new Son();
        son.sing();
        System.out.println(son.a);
    }

}
class Father{
    int a=1;
    int b=10;
    public void sing(){
        System.out.println("father sing song");
    }

}
class Son extends Father{
    int a=2;
    int b=20;
    @Override
    public void sing(){
        System.out.println("son sing song");
    }
}
